The World's 100 Most Powerful Women by Forbes

Europe is in debt crisis, the Middle East is shaking and there's market panic at home. It is against this backdrop that we present the World's 100 Most Powerful Women.

The women on this list were chosen not just for being on top but for being smack in the middle of Richter-registering events--and more. Their power derives from money and might, yes, but also (thanks to old, new and social media) reach and influence.

This year's No. 1 in the ranking, German Chancellor Angela Merkel--recognized as the "undisputed" leader of the EU--is key to curing what ails the euro zone. As the Arab spring turns into the autocrats' summer, No. 2-ranked U.S. Secretary of State Hillary Clinton provides encouragement to dissidents, while Facebook's Sheryl Sandberg (No. 5) and Twitter's Katie Jacobs Stanton (No. 56) empower the rebels storming the barricades with an uninterrupted newsfeed--or a way to report in 140 characters or less.

The Power 100 Women are not just newsmakers--they are custodians of the news. Jill Abramson (No. 12) makes her first appearance as new executive editor of the New York Times. BBC News, run by Helen Boaden (No. 51), reaches some 34 million viewers weekly. Probably best known are the televised journalists: ABC's Christiane Amanpour (No. 44) and Diane Sawyer (No. 47), Ann Curry of TODAY (No. 66) and On The Record's Greta Van Susteren (No. 75).

Other famous faces make the list this year because they have exploited their celebrity status to build global businesses or champion humanitarian causes. Lady Gaga (No. 11) raised over $200 million to fight HIV/AIDS while Angelina Jolie (No. 29) continues her work as a U.N. ambassador.

The United Nations counts two power women in the ranks: Josette Sheeran (No. 30) of the World Food Programme, the world's largest humanitarian agency, and Helen Clark (No. 50) of the UN Development Programme. Other nonprofit leaders include CARE USA's Helene Gayle (No. 36) and Judith Rodin (No. 71) president of the 98-year-old Rockefeller Foundation.

Ten percent of the list has bank accounts in the 10 figures, including the self-mades Oprah (No. 14) and J.K. Rowling (No. 61). These billies do more than just eat bonbons: Walmart heiress Alice Walton (No. 85) is opening her preeminent collection of American art to the public with the Crystal Bridge Museum on 11/11/11, while Georgina Rinehart (No. 19), the richest woman in Australia--and said to be on track as the richest person in the world in 2012--is using her wealth to campaign against national environmental reforms and taxes.

There's nothing static about the list. Nearly half the women are first-timers or are back after dropping off. Some changed jobs since last year. Most were promoted but some changed tracks altogether or are newly elected to office--all evidence that women are moving up the pipeline.

Christine Lagarde (No. 9), France's former finance minister, for example, is now managing director of the I.M.F., and Ngozi Okonjo-Iweala (No. 87) switched from the World Bank to finance minister of Nigeria. Susan Wojcicki (No. 16) was upped to SVP at Google and Denise Morrison (No. 80) was promoted from COO to CEO for Campbell Soup. She's one of 29 CEOs here. Dilma Rousseff (No. 3) and Yingluck Sinawatra (No. 59) were elected as president of Brazil and prime minister of Thailand, respectively, now in a club of eight heads of state on the list.

Our members come from politics, business, technology, media, entertainment and nonprofit and were ranked by three metrics: dollars, a traditional and social media component and power base points. We looked at if they hold sway over multiple spheres of influence rather than have a single source of authority.

This is new to the 2011 FORBES 100 Most Power Women methodology and reflects a more dynamic and diverse power that impacts greater numbers of people. For a description of our methodology, full bios, slide shows, videos and more visit www.forbes.com/power-women.